A new PMMA-microchip device for isotachophoresis with integrated conductivity detector

This report describes the design, fabrication and use of new microanalytical devices based on polymer substrates for electrophoretic methods, especially isotachophoresis. The devices are fabricated by hot embossing and are sealed with a thin plexiglas cover plate which contains platinum electrodes for contact conductivity detection and power supply. Poly(methylmethacrylat) (PMMA) shows good prospects for the development of low-cost disposable or semi-disposable microanalytical devices. Two different chip-designs are introduced to demonstrate the advantages of the manufacturing procedure and the use of poly(methylmethacrylat) as substrate material. The channel system on the chips is equipped with two sample loops with different volumes to take advantage of the high sample loadability and the enrichment qualities of isotachophoresis. In addition, two separation columns allow two-dimensional on-column ITP–ITP- and CZE–ITP-coupling. Separations of organic acids are used to demonstrate the principle of the isotachophoresis-chips.